Monthly Archives: October 2011

Data sources for WRF

Some of the useful data sources for WRF:

Dataset Resolution Link
GFS Final Analysis 1 degree http://dss.ucar.edu/datasets/ds083.2/
GFS Final Analysis 0.5 degree http://dss.ucar.edu/dsszone/ds335.0/index.html?g=9
Recent GFS Analysis and Forecasts 0.5 degree  ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod
PreBUFR obs NA http://dss.ucar.edu/datasets/ds337.0/
SST data 0.5 ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/sst.
Archived GFS forecast 1 degree
0.5 degree
http://nomads.ncdc.noaa.gov/data.php?name=access#hires_weather_datasets
Archived GFS forecast 1 degree http://dss.ucar.edu/datasets/ds335.0/MSS-rqst-list.html?g=10
Blended ocean winds 0.25 degree http://www.ncdc.noaa.gov/oa/rsad/air-sea/seawinds.html
Dataset Resolution Link
Dataset Resolution Link

GFS final analyses are readily available archived back to 2000. However, using these as boundary conditions all the way through a forecast is cheating. At the time of doing a forecast, you only have one analysis available, and have to rely on a global forecast for your future boundary conditions.

Archived GFS forecasts are available from NOMADS. These are kept ‘online’ for 1 year. Archived forecasts are available ‘offline’ back to 2005 for 1 degree and 2006 for 0.5 degree forecasts. However, my requests for online data didn’t match any files. Offline means you have to wait for the request to get processed, and can only request 14 days at a time.  Also the offline system will close to new order when 45 orders are sitting in the queue.  A lot of good links to NOMAD servers are available here: http://nomad5.ncep.noaa.gov/

The GFS forecast cycle is at 00, 06, 12 and 18, and the forecast interval is 3 hours from out to 180 hours. The resolution of the GFS forecast grids are:

  • #004 0.5 degree (output in grib 2 format)
  • #003 1.0 degree
  • #002 2.5 degree

Forecast verification in MET

This week I almost managed to get the MET verification tool working with WRF, with a lot of excellent help from met help at UCAR.   It’s been quite a bit of work but I’m hoping it saves me some time in the long run.

The program flow goes something like this:

Will post up some more interesting results next week.

WRF in Google Earth

Traditionally weather maps aimed to present an enormous array of data as a simple output: a sun, a sun behind a cloud, or some rain.  Or possibly a cloud getting blown along by a face.  That’s great, as what most people want to know is: will it rain or not?

But this hides is the beauty and complexity behind the weather, we are immersed in a big mass of swirling fluid, rising, falling, heating, cooling.  Enormous amounts of energy are transported around the world, air masses collide, jet streams arc and split. In the midst of this, occasionally everything stills, and there is hardly a breeze.  It’s one big never-ending dance, and it looks beautiful.

That’s why I’m trying to put forecast data into Google Earth, because you get a real feel for the fact the UK’s weather doesn’t end at the edge of the map.

Using NCL and some code from rpavlick, this is my first attempt to put a forecast into Google Earth. At the moment it is just a picture, but hopefully I’ll get a Google Earth gadget working soon.